Selective magneto-luminescence spectroscopy of donor-acceptor pairs in n-GaAs

The results of selective magneto-luminescence measurements of donor-acceptor pairs in n-type GaAs are discussed. The experimental data are compared with the calculated energy levels of a hydrogen-like atom in a magnetic field, enabling us to identify a large number of high angular momentum states of the hydrogen-like impurity in magnetic fields. It is shown that in addition to intra-donor transitions, the spin-flip excitations of donor-acceptor pairs involving heavy and light holes can be observed, yielding information about g-factors for heavy and light holes. For the pairs with separations smaller than the donor Bohr radius, a strong modification of the SPL spectrum is observed. This effect is discussed in terms of modification of the acceptor ground state induced by the interaction with a neighbouring donor centre